Antenna



FIG. 1 is an upper rear perspective view of an antenna.

FIG. 2 is a front elevation view of the antenna of FIG. 1.

FIG. 3 is a bottom plan view of the antenna of FIG. 1; and,

FIG. 4 is a left side elevation view of the antenna of FIG. 1. 

CLAIM The ornamental design for an antenna, as shown and described. 